It's a fun little game! A have a couple of ideas and things to change:
Add sound effects, Bosca ceoil is great for music and SFDesigner is ground for making some basic sounds.
Add a way to view what each ability does for each character
The wizard is way super overpowered you can easily fireball spam any enemy most battle the wizard wins unless everyone else was to team up on him, I recommend making him weaker maybe he can only use a fireball once per turn.